Looking for GPS modules
I’ve been surfing the internet looking for ideas for my autopilot system. The most important sensor we need, is a GPS. Several important factors that influence my choice are:
- Weight!
- Accuracy
- Update rate
- Cost
- Easy to use
Right now I found two candidates:
a Sirf Star III based module (1Hz update, 10m accuracy, 17 gram)
and some from µblox like the SAM-LS (4Hz update, 2.5mr accuracy, 23 gram) used by the paparazzi project. I prefered the SAM-LS because if it’s high update rate and great accuracy:
Unfortunately, it uses some weird flex cable to connect, so purchasing it could be a risk when I wouldn’t find the right connector. In the the RCB-4H (basically a development board; 17 grams and requires an active antenna) might be a better choice…
To be continued :-)
1 June 2006, 15:24
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I want to say great blog. The articles are very informative keep them coming.
— Pete, 8 June 2006, 15:32 | #
I can strongly recommend the u-blox modules. As well as the SAM-LS you can also get surface mount modules (LEA and TIM series) that you can mount directly on your circuit board and attach an antenna of your choice to. Watch out for the RF PCB layout though, we had interference problems where our 400 MHz CPU had a clock harmonic that was jamming the GPS and preventing getting a fix (this is not u-blox specific, it could happen with any GPS system if your CPU has a harmonic at or around the GPS frequency, or if you have a shoddy RF circuit layout on the PCB). Good luck!
— Hugo, 16 June 2006, 03:06 | #
But those SAM-LS modules are pretty expensive compared to the SiRF Star ones?
— Jerry, 9 August 2006, 10:46 | #
Hmmm no,
I heard that if you buy them in large quantities, they can be around 30$
— Tom, 9 August 2006, 11:54 | #
But ublox themselves sell samples for 95 euros excluding local sales tax. Surely you’d have to order A LOT to get the price down to $30 for the end user!!!
— Jerry, 12 August 2006, 15:19 | #